The Walker Horde

Wildfire infection (Whenever this creature deals combat damage to a creature, that creature becomes a black Zombie in addition to its other types and gains wildfire infection and decayed.)
Whenever a Zombie enters and whenever a creature gains wildfire infection, Amass Zombies 1 Whenever one or more +1/+1 counters are put on a Zombie you control, each opponent loses 1 life and
you gain 1 life.